The other day my nephew was browsing a website and called me to ask about a box he’d seen on one of the pages. The box turned out to be a Captcha and I explained to him what their basic function is: to distinguish between human users and computer programs. I’d never really taken any notice of them up to then but curiosity and a little research showed what else they were useful for.
Automated spam comments on blogs has to be the bane of every blogger’s life; using a Captchas will ensure that only humans can enter what are hopefully genuine comments onto a blog and all without the need for them to sign up before doing so.
Dictionary attacks on password systems is another area where Captchas are useful. Computerised systems will make numerous attempts to crack a password and Captchas go some way to preventing this by requesting the programme to enter the characters shown in the box after a pre-defined number of failed logins.
Other occasions where the use of a Captcha is advisable is when signing up for something free such as email accounts, newsletters, competitions etc, in fact anything that requires a sign up procedure on a website would probably benefit from a Captcha, at least for the foreseeable future.
I say the foreseeable future because as computer programmes become ever more sophisticated it’s not beyond the realms of possibility that at some point a way will be found that enables a programme to read Captcha characters or bypass the system altogether, and if you think that sounds impossible, take a look at the astonishing advances in computer technology over the last ten or even five years and think again.
Until next time.
